Climate Change: What are your thoughts?

This column, the first in a series on climate change, provides a very brief overview of climate-change physics and asks for your thoughts. Are you convinced of human-caused climate change? What persuaded you to accept or reject it? This is a huge topic, so the more I know of your convictions, doubts, questions or concerns, the better I can cover points of greatest interest to you. ConervationErwin@gmail.com or Rebecca Cummings, c/o The Erwin Record, 216 Gay St., Erwin, TN 37650. The Precious Jewel In the famous Apollo 17 picture, Earth looks like a blue marble with swirling clouds suspended alone in the deep blackness of space. Commonly, the surrounding black expanse is cropped away as unimportant, but that is possibly the most striking feature, namely, how alone we are in the vastness of space. Earth is a precious jewel. We need to take care of this oasis in space, for there is no back-up planet. The Greenhouse EffectProbably from the beginning of human life, people have known that the sun warms us. As our understanding grew, we learned that space is deathly cold and yet Earth manages to stay warm thanks to our sun and the atmosphere. As sunlight passes through our atmosphere, some is reflected back to space from clouds and ice. The rest is absorbed to produce plant growth or heat. When you have a warm planet and frigidly cold space, that warmth radiates into space. An excellent example is Mars, where the sun warms its surface, but with almost no atmosphere, that heat immediately radiates back to space resulting in an average -80°F temperature. Fortunately, Earth has an atmosphere that absorbs some of the radiated heat to create a warm blanket around us. 98% of our atmosphere is nitrogen and oxygen which provide no protection from heat loss, because having only 2 atoms each, they cannot absorb heat. Fortunately, we have greenhouse gases (GHGs) in our atmosphere - water vapor, carbon dioxide, methane, nitrous oxide, and other lower-concentration GHGs. These molecules have three or more atoms and this more complex geometry enables them to flex enough to absorb heat. As heat radiates away from Earth's surface, most of it escapes into space. But some of it bumps into a GHG and is absorbed. When that excess heat is eventually released, some of it radiates back toward Earth thus creating the warm-blanket effect. So, GHGs can be a good thing. The ProblemHuman actions are increasing the amount of GHGs in our atmosphere at an unprecedented rate. The more GHGs, the greater the odds that heat radiating from Earth will be captured by a GHG and radiated back to Earth. Future articles will delve more deeply into the consequences and evidence of increased GHG levels as well as other topics from your feedback. I look forward to hearing from you. There are excellent videos on-line of simple experiments you can run yourself that demonstrate carbon dioxide's ability to absorb heat. I'm happy to send links upon request. ••• Rebecca Cummings is a retired engineer living in Unicoi who, along with her husband of 40 years, enjoys exploring the beauty of the mountains, streams and waterfalls. Her deep Scottish heritage feeds a strong drive to conserve money and resources and to protect the area's beautiful environment for future generations. Email her at ConservationErwin@gmail.com.